Refrigerating apparatus



pril 7, 1936.1

Filed May 28, 1950 ED- STATES PATENT OFFICE,

nsrmoeaamo marinus v 4Harry B. Hull, Dayton, Ohio, assigner, by mesne assignments, to General Motors Corporation, a

` corporation o! Delaware Application May 2s, leso, serai Massese This invention relates to refrigerating apparatus end methods and particularly to that type oiapparatus and method which maintains automatically two zones at dierent temperatures.

An object of this invention is to provide a method and apparatus for maintaining two or more sones at different temperatures by means oi" 'a closed circulating system containing a volatile refrigerant at the same pressure throughout the closed system and in which the operation of the closed system is controlled in accordance with -conditions prevailing in the apparatus.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing. wherein a preferred form oiv i the present invention is clearly shown.

In the drawing: i

Fig. 1 is a view, partly in vertical cross-section, and partly in elevation, and partly diagrammatic, oi. an apparatusembodying features of this invention;

Fig, I2 is an enlarged elevation of a'portion oi rig. i; and

Fig. 3 is a vertical cross-section taken transversely to Fig. 2.

According to this invention, two or more zones may be maintained at relatively low and relatively higher refrigerating temperatures by cyclically exposing a volatile refrigerant to'a vaporizing action in one of said zones and condensing the refrigerant in another of said zones, while said.

refrigerant is maintained throughout at substantiallythe same pressure, by utilizing conditions in the method or apparatus for restricting the normal flow of refrigerant.

Features of this invention may thus include means for maintaining a first zone 20 at a relatively low temperature and means 22 Afor maintaining' a second zone or body to be cooled 2l at a higher temperature. The means 22 preferably is a closed circulating system, which maycontain a volatile refrigerant substantially at the same pressure (neglecting slight hydrostatic heads) throughout the closed system22.V Means'22 may also include an .evaporator 23 adapted to per- :form the cooling for the zone 2i. The means 22 may also include a condenser 24 in the first zone 20. A connection for the iiow of refrigerant between the evaporator and the condenser may includes. liquid'line 25 and -a vapor line 26 so that refrigerant condensed in the condenser 2t may low through the line 25 to the evaporator 23 and. the refrigerant evaporated in the evaporator 2t may pass as a vapor through the line 2d to the condenser 24.

'The normal ow oi refrigerant between the condenser 24 and the evaporator 23 may be varied in accordance with conditions in the apparains. That is, the flow which normally would tions in the closed circulating system 22, maybe provided for varying the normal ow ol refrigerant. Preferably this normal ow of refrigerant is varied in the vapor line A2li by throttling the yl5 new oi vaporized refrigerant in the vapor line 2t. This may be accomplished by providing a bellows 28, responsive to pressure conditions in the closed system 22 for operating a valve 29 in the vapor line. Thus itis to be seen that when the valve 2t partly or completely .throttles the line 26, furthm' evaporation in 'the evaporator 23 causes liquid refrigerantfrom the evaporator to ow in the insulated line 25 towards thecondenser 24. This varies the amount of liquid re- 25 frigerant in theevaporator 28 and thus varies the cooling capacity of the evaporator.

The bellows 2B may be made responsive to pressure conditions in the system 22 by providing a passageway 30 connected to the portion 3| 30 i of the vapor line 26. A spring 32 is adapted to resist the operation of the bellows 28, so that when the pressure in the closed system 22 drops. the bellows 28 tends to close the valve 29, and

when the pressure in the system 22 increases, the 35V bellows 28 tends to open. the valve 29. A manual adjustment 33 may be provided for varying the tension of the-spring 32 in order to vary the conditions under Which'the valve 29 operates, to suit the individual requirements of the user. 40

The zone 20 may be maintained at a relatively low temperature by, any suitable means.

vThus ajoil 34 may be placed in thermal contact with the condenser 24. The coil 34 may be refrigerated by any suitable means. 'Ihus it may 45 be refrigerated by providing a primary refrigerant evaporator, including, for example, an expension valve 35 which expands refrigerant en- .tering the pipe 3G leading to the coil 34. The expanded refrigerant may pass through the pipe 2 assente liquid refrigerant pipe 4| with 'the expansion Valve 35.

The zone 20 may be maintained at any desired predetermined temperature. Thus it may be 5 maintained at a substantially constant temperature between predetermined temperature limits by any suitable means, such as by a thermostat 42 submerged in the brine 43 surrounding the coil 34. The thermostat 42 may operate a snap switch 44 through the medium of an expansible bellows 45 connected by the line 46 with the thermostat 42. The snap switch 44 may control the starting and stopping of the motor 41 which drives the compressor 38, thus maintaining the l5 zone 20 within predetermined temperature limits.

If the zones and 2| are part of a domestic mechanical refrigerator, it may be desirable to provide means for freezing ice cubes or the like. This may be accomplished by providing sleeves 20 50 in the brine tank 5I for the reception of ice cube trays 52. The zone 2| may be formed by the lining 55 which forms a food compartment and is insulated by means of the insulation 53. The zone 20 may be insulated from the zone 2| by means of the insulation 54.

In this particular embodiment, the zone 2| tends to be maintained at a predetermined temperature by the variation of the cooling action of the evaporator 23 acting under the influence of the means 21. Thus when the evaporator 23 is cooled sufficiently by the evaporation of refrigerant, the pressure in the system 22 drops to such a point that the valve 29 is partly or wholly closed. Any evaporation in 23 in excess of that required to produce the amount of vapor passing the valve 21 tends to create an excessive amount of vapor in the upper part of the evaporator 3. This forces liquid refrigerant from the evapora r .-23 through the insulated pipe 25 towards the condenser 24. Since the amount of liquid refrigerant in the evaporator 23 is thus reduced, its cooling action on the zone 2| is reduced. On the other hand, when the temperature of the refrigerant in the evaporator 23 rises, the pressure in the system 22 also rises, so that the valvev23 is opened and permits all of the liquid refrigerant possible to flow into the evaporator 23. 'Ihis increases the cooling power of the evaporator to its maximum capacity at the refrigerant temperature prevailing. This action tends to maintain the average temperature of the evaporator 23 and of the zone' 2| substantially constant. This permits the maintenance of the food compartment at any desired temperature independently of the temperature prevailing in the zone 20.

While it may be stated that the pressure prevailing in the closed circulating system 22 is governed partly by the temperature in the evaporator 23 and partly by the temperature in the condenser 24, it is to be noted that the temperature of the liquid in the system 22 is the predominating and practically sole factor in the determination of the pressure in the system 22. For this reason, when the temperature in the zone 2| tends to rise above the limit desired, the liquid in the evaporator 23 is also heated. This creates a relatively high refrigerant pressure in the system 22 and opens the valve 29, thus admitting all of the liquid refrigerant into the evaporator 23 and increasing its cooling capacity to a maximum in order that it may prevent the undesired rise in temperature in the zone 2|. Conversely, when the temperature in the zone 2| tends to fall below the desired limit,

the liquid refrigerant in the system 22 is also cooled and its pressure is likewise' reduced. This permits the valve 29 to close and thus eventually force some of the liquid refrigerant from the evaporator 23 into the line 25. This decreases the cooling capacity of the evaporator 23 and s prevents the undesired fall in temperature in the zone 2|.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms lo might be adopted all coming within the scope of claims which follow.

What is claimed is as follows:

1. A. refrigerating apparatus comprising means for maintaining a rst zone at a relatively low l5 temperature, means for maintaining a second zone at a higher temperature, said last named means including a closed circulating system containing a volatile refrigerant at substantially the same pressure throughout the closed system, and 20 having an evaporator in said second zone and a condenser in said, first zone, a connection between said evaporator and condenser, and means responsive to pressure conditions in said closed circulating system for varying the amount of 25 liquid refrigerant in said evaporator.

2. A refrigerating apparatus comprising means for maintaining a rst zone at a relatively low temperature, means for maintaining a second zone at a higher temperature, said last named 30 means including a closed circulating system containing a volatile refrigerant at substantially the same pressure throughout the closed system, and having an evaporator in said second zone and a condenser in said ilrst zone, a liquid line and a 35 vapor line between said evaporator and condenser, and means responsive to pressure conditions in said closed circulating system .for causing liquid refrigerant from said evaporator to flow towards said condenser in said liquid line. 4o

3. A refrigerating apparatus comprising means for maintaining a first zone at a relatively low temperature. means for maintaining a second zone at a higher temperature, said last named means including a closed circulating system con- 45 taining a volatile refrigerant Aat substantially the same pressure throughout the closed system, and having an evaporator in said second zone and a condenser in said rst zone, a liquid line and a vapor line between said evaporator and con- 50 denser, and means responsive to conditions in said apparatus for causing liquid refrigerant from said evaporator to flow towards said condenser in said liquid line.

4. A refrigerating method which comprises 55 maintaining a first zone at a relatively low refrigerating temperature, and maintaining a second zone at a higher refrigerating temperature by cyclically exposing a volatile refrigerant to a i vaporizing action in said second zone and con-60 densing said refrigerant in said first zone, said refrigerant being maintained at substantially the same pressure while vaporizing and condensing and utilizing the pressure conditions of said refrigerant to vary the amount of liquid refrigerant 65 exposed to vaporizing action.

5. A refrigerating system of the thermo syphon type comprising an expansion zone, a condensing zone, means for restricting the flow of gas from the expansion zone to the condensing zone and 70 an insulated connection between the condensing zone and the expasion zone for minimizing heat ow into the liquid refrigerant flowing from the condensing zone to the expansion zone.

6. A closed thermo syphon type of refrigerat- 75 @i w having a condensing clement and n heat absorbing clement receivinii liquid refrigerant by gravity circulation from said condenser' and in which a volatile refrigerant is utilized onri in which the refrigerant iiows in a predetered pointue method of regulating the tcm nera of the neat nhcorbina element of auch orc which comp throttiinu the now ci uur refrigerant inone direction and causing o ncn-rravitationni iiow of liquid refrigerant i w uvz the heat absorbing element' to the condeno Tr niet oi the ry in the opposite direc u i. closed thermo oyphon type oi' refrigerati ryrtem having a condensing element and o neat absorbing;4 elementv receiving liquid refriget by gravity circulation from said condenser and in which a. volatile refrigerant is utilized and in which the refrigerant flows in a predetermined nein, ine method ci' regulating thetem i oi' heut absorbing-element cf mich union comprises tnrottiing the iiow of saeeour recerant from the heat absorbing element to 'the condensing element in one direction and cuni i im; n non-gravitational flow of liquid refrig-n ernnt irom the heat absorbing" element to the conde' element ci the in the cte c iw i type oi refrigerai c i ii a im i eiement and e. neer chromium ernmt receiving liquid reim eri nu' uravity circuiation imm acid conde and in which a voiae refrigerant nom in n :ore-

:im nain. ci i for thx-ot the now 'ci cnrteoue rei'rierant in one direction and menne cane 4n non-vitaticnai now ci iiuuiri $,MONiid 4 i refrigerant'.fromthe heat theconficnoimzeiexnentofiheintiaeop-l .e'rein poeite direction.

9. .A clsedfthermo syphnn type of reinsercisystem comprising a condensing element and avheat absorbing element receiving liquid refrigerant by gravity circulation from raid condenser vand in which a volatile refrigerant iiow in n- 'predetermined nath, means i'or throttling the n of gue refrigerant in one direction so i for causing a non-gravitationci now oi liquid refrigerant from the heat absorb! eiement to the condensing element of the system in the opposite direction and an insulated connec tion between the heat absorbing element and the condensing element.

v iu.. In a closed thermo syphon type reir-igernting system ihe procesa of refrigeration which comprises graritationoiiy circulating volatile're- .frierunt from n condensing zone through n non.

heat exc 11 i zone to a heat interchanger and automatic varying the surface oi contact Toeii. in a winni system, in ccbinaticn, a n i Yreieratin means havin@ n none et reintiveiy low temperature, n seednrr closed circuit ww wl fr: n' condenser in thermai en t u raid acne, an evaporator in the exe min a. dy to 'be cooieoi. and me ier cnuc wu the iiquid ievei to ne varied in said evnrator in reoponse to vapor-pr i i chap.. acterietice oi reid recon cloned circuit.

een the iiuuid refrigerant ami time heet mier--v a volatile reirigerant I clment t0 l 

